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UNIT-1
Digital Pulse Modulation
Elements of Digital Communication Systems:
Fig. 1 Elements of Digital Communication Systems
1. Information Source and Input Transducer:
The source of information can be analog or digital, e.g. analog: audio or video
signal, digital: like teletype signal. In digital communication the signal produced by
this source is converted into digital signal which consists of 1′s and 0′s. For this we
need a source encoder.
2. Source Encoder:
In digital communication we convert the signal from source into digital signal
as mentioned above. The point to remember is we should like to use as few binary
digits as possible to represent the signal. In such a way this efficient representation
of the source output results in little or no redundancy. This sequence of binary digits
is called information sequence.
Source Encoding or Data Compression: the process of efficiently converting
the output of whether analog or digital source into a sequence of binary digits is
known as source encoding.
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